GRK-Biased Activation Via β2-Adrenergic Receptors in Human Skeletal Muscle (GAIN)
G Protein-Coupled Receptor Kinase (GRK)-Biased Signaling Via β2-Adrenergic Receptors and Downstream Activation and Its Role for Protein Synthesis-Regulating Kinases, Function and Receptor Desensitization in Human Skeletal Muscle
This longitudinal mechanistic physiological study examines biased β2-adrenergic receptor (β2-AR) signaling in human skeletal muscle, with emphasis on G protein-coupled receptor kinase (GRK)-mediated pathways. Participants will receive daily oral dosing of the GRK-selective long-acting β2-agonist ATR-258 for 8 weeks. Muscle biopsies and physiological measurements will quantify GRK-, cAMP/PKA-, and β-arrestin-related up- and downstream signaling, fiber-type specificity, and potential receptor desensitization with repeated stimulation along with functional read-outs, tissue distribution, cardiovascular response and tolerability.
Studieoversikt
Status
Status
Forhold
Forhold
Intervensjon / Behandling
Intervensjon / Behandling
Detaljert beskrivelse
Healthy men with overweight/obesity will complete an 8-week intervention with daily oral ATR-258 (0.5-2.5 mg/day). On experimental days (Days 1, 15, 29, and 56), β2-AR signaling sensitivity will be assessed before and after stimulation (1-2, 4, and 8 hours) using blood biomarkers, hemodynamics, indirect calorimetry, and lower extremity muscle function/power testing. Muscle biopsies (vastus lateralis) will be obtained at rest and 4 hours after stimulation on Days 1, 29, and 56 to quantify downstream signaling (GRK, cAMP/PKA, β-arrestin), phosphorylation of rpS6/mTOR/Akt, β2-AR content, and muscle fiber morphology.
Studietype
Studietype
Registrering (Faktiske)
Registrering
Fase
Fase
- Fase 2
Kontakter og plasseringer
Studiesteder
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Copenhagen, Danmark, 2100
- University of Copenhagen, August Krogh Section for Human & Molecular Physiology
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Deltakelseskriterier
Kvalifikasjonskriterier
Kvalifikasjonskriterier
Alder som er kvalifisert for studier
Tar imot friske frivillige
Kjønn som er kvalifisert for studier
Beskrivelse
Inclusion Criteria:
- Healthy men
- Age 21-45 years
- BMI 25-35 kg/m^2
- Body fat percentage 25-40%
- Lean Mass Index 14-22
Exclusion Criteria:
- Regular use of or allergy to β2-agonists
- Serious adverse reactions to β2-agonists
- Current smoker
- Regular use of medication (except OTC allergy or analgesics)
- Abnormal ECG before or after β2-AR stimulation
- Hypertension
- Reduced kidney function (eGFR < 90 ml/min/1.73m^2)
- Cardiovascular, metabolic, gastrointestinal, renal, or pulmonary disease
- Psychiatric or neurological disorders affecting compliance/safety reporting
- Cancer history within the last 5 years
- Substance abuse or alcohol intake >14 units/week
Studieplan
Hvordan er studiet utformet?
Designdetaljer
- Primært formål: Grunnvitenskap
- Tildeling: N/A
- Intervensjonsmodell: Enkeltgruppeoppdrag
- Masking: Ingen (Open Label)
Antall våpen
Våpen og intervensjoner
Deltakergruppe / ArmDeltakergruppe / Arm |
Intervensjon / BehandlingIntervensjon / Behandling |
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Eksperimentell: ATR-258
Daily oral ATR-258 |
Daily oral ATR-258 for 8 weeks with repeated experimental assessment days (Days 1, 15, 29, 56). |
Hva måler studien?
Primære resultatmål
Primære resultatmål
Resultatmål |
Tiltaksbeskrivelse |
Tidsramme |
|---|---|---|
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Intensity of β2-AR downstream signaling pathways (e.g. GRK, cAMP/PKA, β-arrestin, rpS6) in type I and type II muscle fibers
Tidsramme: Before and 4 hours after ATR-258 ingestion on day 1, 29, and 56.
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Assessed in vastus lateralis biopsies at rest |
Before and 4 hours after ATR-258 ingestion on day 1, 29, and 56.
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Sekundære resultatmål
Sekundære resultatmål
Resultatmål |
Tiltaksbeskrivelse |
Tidsramme |
|---|---|---|
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Phosphorylation of rpS6, mTOR, and Akt in type I and type II muscle fibers
Tidsramme: Day 1, 29 and, 56.
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In response to ATR-258 ingestion |
Day 1, 29 and, 56.
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Lean/fat mass
Tidsramme: Day 1, 15, 29, and 56
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Measured by DXA scan |
Day 1, 15, 29, and 56
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Muscle function
Tidsramme: Pre and post 8 weeks of daily ATR-258 ingestion. Post visit conducted 2-5 days after last day of ATR-258 ingestion.
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Participants will perform lower extremity peak exercise and a one-legged knee-extensor exercise protocol to exhaustion before and after the full intervention to assess muscle power and endurance |
Pre and post 8 weeks of daily ATR-258 ingestion. Post visit conducted 2-5 days after last day of ATR-258 ingestion.
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Peripheral glucose clearance including OGTT-derived outcomes
Tidsramme: Pre and post 8 weeks of daily ATR-258 ingestion. Post visit conducted 2-5 days after last day of ATR-258 ingestion.
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Pre and post 8 weeks of daily ATR-258 ingestion. Post visit conducted 2-5 days after last day of ATR-258 ingestion.
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β2-adrenergic receptor content in type I and type II muscle fibers
Tidsramme: On day 1, 29 and 56
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Measured by western blotting |
On day 1, 29 and 56
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Resting metabolic rate (incl. carbohydrate and fat oxidation)
Tidsramme: Before and 1, 2, 4 and 8 hours after ATR-258 ingestion on day 1, 15, 29, and 56.
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Measured by indirect calorimetry |
Before and 1, 2, 4 and 8 hours after ATR-258 ingestion on day 1, 15, 29, and 56.
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Femoral arterial blood flow
Tidsramme: Before and 1, 2, 4 and 8 hours after ATR-258 ingestion on day 1, 15, 29, and 56.
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Measured by Doppler. |
Before and 1, 2, 4 and 8 hours after ATR-258 ingestion on day 1, 15, 29, and 56.
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Continous ECG and heart rate
Tidsramme: A 5-day baseline period, and day 1-5, day 15-20, and day 29-34 of ATR-258 administration.
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Participants will wear a Holter-device for 4 x 5 days to continuously measure ECG and heart rate. The periods will be after the screening (baseline period), and after trial days on Day 1, 15, and 29. |
A 5-day baseline period, and day 1-5, day 15-20, and day 29-34 of ATR-258 administration.
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Muscle fiber cross-sectional area (type I and type II)
Tidsramme: Day 1, 29, and 56
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Measured by histochemical analysis |
Day 1, 29, and 56
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Maximal electrically-stimulated muscle force development and relaxation
Tidsramme: Pre and post 8 weeks of daily ATR-258 ingestion. Post visit conducted 2-5 days after last day of ATR-258 ingestion.
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Isometric quadriceps. Measured seated with leg in 90 degree angle and attached to strain gauge. |
Pre and post 8 weeks of daily ATR-258 ingestion. Post visit conducted 2-5 days after last day of ATR-258 ingestion.
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Samarbeidspartnere og etterforskere
Sponsor
Sponsor
Samarbeidspartnere
Samarbeidspartnere
Studierekorddatoer
Studer hoveddatoer
Studiestart (Faktiske)
Studiestart
Primær fullføring (Antatt)
Primær fullføring
Studiet fullført (Antatt)
Studiet fullført
Datoer for studieregistrering
Først innsendt
Først innsendt
Først innsendt som oppfylte QC-kriteriene
Først innsendt som oppfylte QC-kriteriene
Først lagt ut (Faktiske)
Først lagt ut
Oppdateringer av studieposter
Sist oppdatering lagt ut (Faktiske)
Sist oppdatering lagt ut
Siste oppdatering sendt inn som oppfylte QC-kriteriene
Siste oppdatering sendt inn som oppfylte QC-kriteriene
Sist bekreftet
Sist bekreftet
Mer informasjon
Begreper knyttet til denne studien
Nøkkelord
Ytterligere relevante MeSH-vilkår
Andre studie-ID-numre
Andre studie-ID-numre
- ATR
- H-25045258 (Annen identifikator: Danish Ethics Board)
Plan for individuelle deltakerdata (IPD)
Planlegger du å dele individuelle deltakerdata (IPD)?
Legemiddel- og utstyrsinformasjon, studiedokumenter
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